WEEK 7-histopath Flashcards
(20 cards)
is considered the primary technique for obtaining
diagnostic full-thickness skin specimens. It requires basic general
surgical and suture-tying skills and is easy to learn. The technique
involves the use of a circular blade that is rotated down through the
epidermis and dermis, and into the subcutaneous fat, yielding a 3- to 4-
mm cylindrical core of tissue sample.
Punch biopsy
This is done by placing a drop of secretion or sediment upon one slide and facing it to another clean slide. The material
disperses evenly over the surface of the two slides. Slight movement of
the two slides in opposite directions may be necessary to initiate the
flow of materials. The two slides are then pulled apart with a single
uninterrupted motion, and the specimen is placed under the microscope
for immediate examination, or applied with vital stains.
Pull-Apart
Once tissues are removed from the body, their proteins and cells are
digested and broken down by their own enzymes, independent of a bacterial
action. This process is known as
autolysis
where tissue is scooped or spooned to remove tissue or
growths from body cavity such as endometrium or cervical canal.
Curettings
a supravital stain may be placed at the junction of the slide and
the cover glass, and allowed to be absorbed by the tissue through capillary
attraction.
Squash Preparation (Crushing)
Types of Smear Preparation
Streaking, Spreading, pull apart
A selected portion of the material is transferred to a
clean slide and gently spread into a moderately thick film by teasing
the mucous strands apart with an applicator stick. It is a little more
tedious than streaking, but has the advantage of maintaining cellular
interrelationships of the material to be examined. It is especially
recommended for smear preparations of fresh sputum and bronchial
aspirates, and also for thick mucoid secretions.
Spreading
IS THE SIMPLEST, LEAST INVASIVE TEST AND USES THE SMALLEST NEEDLE TO SIMPLY REMOVE CELL FROM THE ARE OF ANORMALITY
FINE NEEDLE ASPIRATION
takes out even more surrounding tissue. It takes out
some of the abnormality, but not all. The doctor will slice into the lesion
and remove only a portion of it. If the lesion is found to be cancerous,
further surgery may be needed to remove or excise the entire lesion.
incisional biopsy
-With an applicator stick or a platinum loop, the material is
rapidly and gently applied in a direct or zigzag line throughout the slide,
attempting to obtain a relatively uniform distribution of secretion. Too
thin or too thick smears have to be avoided, since they make the tissues
unsuitable for examination.
Streaking
This is a special method of
smear preparation whereby the surface of a freshly cut piece of tissue is
brought into contact and pressed on to the surface of a clean glass slide,
allowing the cells to be transferred directly to the slide for examination by
Phase Contrast microscopy or staining for light microscopic study. It has an
added advantage in that the cells may be examined without destroying their
intercellular relationship.
Touch Preparation (Impression Smear)
is a process whereby a selected tissue specimen
is immersed in isotonic salt solution such as normal saline or Ringer’s
solution in a petri dish or watch glass, carefully dissected with a needle
and separated by direct or zigzag spread using an applicator stick.
Teasing or Dissociation
The method of preparing the smear differs
depending on the nature of the material to be examined.
Smear Preparation
where small fragments of tissue are “shaved” from a
surface (usually skin).
Shave biopsy
generally removes the entire area in question.
excisional biopsy
is a process whereby small pieces of
tissue (not more than one mm. in diameter) are placed in a microscopic slide
and forcibly compressed with another slide or with a cover glass.
Squash Preparation (Crushing)
removes not only cells, but also a small amount of
the surrounding tissue. This provides additional information to assist in
the examination of the lesion.
Core needle biopsy
It is either stained with a supravital dye or
examined unstained by Phase Contrast or Bright Field microscopy. It has
the advantage of permitting the cells to be examined in the living state. The
use of the phase contrast microscope greatly increases the structural detail
of the cells examined in the living state, allowing movement and mitotic
division to be observed. The application of certain stains such as methylene blue can be also of great value. The preparations, however, are not
permanent.
Teasing or Dissociation
This is
useful for preparing smears of thick secretions such as serous fluids,
concentrated sputum, enzymatic lavage samples from the gastrointestinal
tract, and blood smears. This technique is especially useful in cytological
examinations, particularly for cancer diagnosis.
Smear Preparation
the tissues are usually obtained during surgery,biopsy,autopsy. (True or False)
TRUE
